WO 0069887, WO 04/062560 and WO 06/010921, which are incorporated herein by reference, are previous applications filed by some of the present inventors and describe methods of preparing bioactive molecule coated microcrystals.
For certain applications, such as in the field of drug or vaccine delivery to humans and/or animals, it may be desirable in some instances to provide compositions which, when administered, display a slowed and/or delayed release of the bioactive material. Although such a desired feature has been proposed in the prior art, particles so produced do not always display all of the most desirable properties. For example, in terms of protein coated particles, it is generally desirable to be able to accurately control particle size, maintain protein stability upon storage and display an appropriate release profile for an envisaged use. It may also be desirable to use only non-polymeric materials that are natural or biocompatible and to avoid any chemical or structural modifications to the bioactive material. Additionally it would be desirable to avoid coacervation or emulsification techniques for introducing biomolecules into sustained release particles because the solvents and surfactants used can cause denaturation.
It is an object of the present invention to obviate and/or mitigate at least one of the aforementioned disadvantages.